Geno Smith keeps telling us that there was never anything wrong with his confidence, and if that’s truly the case, there’s little left between the kid’s ears other than a cave full of bats. He was sacked on his first attempt Sunday, then he overthrew a lonesome, arm-waving David Nelson 30 yards downfield on his second attempt by plunking somebody standing 10 yards out of bounds, and by halftime Rex Ryan decided that this 2013 season – and everything it was supposed to represent – required a hard reboot.

We’re hesitant to brand Geno as the worst quarterback ever, because we have only watched the NFL since 1967, but it’s clear that the kid has undergone a whirlwind you rarely see on this level. By now, you’ve moaned at the wretched irony: Nobody expected this team to be in the discussion for a playoff spot in Week 12, and that kismet actually worked against Geno. The more legit this team became, the less his incompetence could be tolerated.

And now the kid goes from everybody’s lovable neophyte to a crashing failure, and it’s too late to flip it, because the season is kaput after this 23-3 recoil against the Miami Dolphins.

“We’ll put the guys in who we think give us the best chance to be successful,” Rex harrumphed when asked about a Plan B, ignoring the fact that 2013 will forever be remembered for Plan A, which involved allowing the opposition to pummel his rookie until his legs started twitching and his chin leaked transmission fluid.

Mathematically, sure, the Jets are alive in that race for sixth. But they never really passed the eye test of a playoff team when the offense was on the field – particularly the last seven weeks, when the starting QB’s touchdown-to-turnover ratio was 1-to-12. So realistically, they’re done, even though everyone else in the AFC -- even the teams with major holes -- seems to have a pulse.

The Jets’ biggest hole isn’t one that can be patched on the fly; their season ends early because they failed to upgrade the one position that keeps you in contention in Week 13.

They gave this kid a one-read, half-a-field offense, but he regressed virtually every step of the way, and it reached the point the Jets themselves were afraid of Geno. There had been some odd media prattle last week about Marty Mornhinweg allowing Geno to air it out, but the Jets knew he isn’t ready to process more than they’ve given him – not now, not this year – and even when they tried to simplify it, they learned something more startling: The opposition can pretty much identify where his read was, which only perpetuates the horror show we saw in Buffalo and Baltimore.

“It’s been a tough three weeks, but I think I’m the best option for this team,” Geno said a few hours after losing his job to Matt Simms. “I think with the way that I work and the progress we’ve made with this offense – I know as of late we haven't produced on the field – but sometimes that happens in the NFL.”

So he’ll continue to wear his pride like a shield against the grim math, but in the most important game he’s played in his career -- with nothing but a 4 MPH wind to deter him -- Geno still threw an interception that led to a Dolphins field goal five seconds before halftime.

And in the most important game he’s coached since the end of 2011, Ryan chucked it all at halftime.

“We were doing absolutely nothing offensively in the first half, so I was just trying to give us a spark,” Rex said.

So now his team grows smaller in the “hopeful” category. At 5-7, the Jets would have to run the table to have any chance at a berth, but tiebreakers aren’t exactly their friends with time running out. A young philosopher named Ryan Tannehill put it this way: “December is the month you step up or fall down” -- an eloquent epitaph for the team he destroyed for 331 yards Sunday. Good for him. He looks like a guy who has been coached very well, and we all know Joe Philbin is a capable QB teacher. It shows.

The Jets, meanwhile, showed that they can lose a must-win home game. They may lose a few more before this slog is over, but their own coach did something interesting Sunday. With the season in free-fall, he took the spotlight off an overmatched rookie, and placed it on himself. And suddenly, it’s getting harder to judge Rex on that 5-4 start, isn't it?